Unhallowed Rites (Blue)

If you've played a non-attack action card this turn, you may play this from your banished zone.

You may put a non-attack action card with blood debt from your graveyard on the bottom of your deck.

Blood Debt

Rulings

From the Monarch release notes

You may still play this from your hand regardless if you’ve played a non-attack action card this turn or not.
A card must have the keyword blood debt to be put on the bottom of your deck, not just reference blood debt.

Keyword notes

Blood Debt - Blood Debt is a new keyword existing on Shadow cards. Shadow cards can inflict a loss of life to access a greater power. At the end of your turn, you lose 1{h} for each blood debt card in your banished zone.

You only lose life at the end phase. Players do not have priority during the end phase.
If you have multiple cards with blood debt, you lose 1 for each instance of blood debt at the end of turn.
Only face-up cards banished with blood debt counts and will lose you . Face-down banished cards have no effects or stats.